This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A385488 #6 Jul 03 2025 01:16:48 %S A385488 3,7,9,6,6,2,3,6,8,8,2,7,5,6,3,7,6,0,0,8,3,8,2,6,0,7,1,4,3,7,2,2,0,3, %T A385488 8,8,6,2,3,1,6,5,4,2,5,7,8,2,2,6,1,8,6,2,3,1,0,4,3,2,0,6,2,7,8,8,0,5, %U A385488 7,5,8,0,7,5,5,9,5,5,9,5,1,4,6,8,0,0,7,5,6,7 %N A385488 Decimal expansion of the surface area of a gyroelongated pentagonal birotunda with unit edge. %C A385488 The gyroelongated pentagonal birotunda is Johnson solid J_48. %H A385488 Paolo Xausa, <a href="/A385488/b385488.txt">Table of n, a(n) for n = 2..10000</a> %H A385488 Wikipedia, <a href="https://en.wikipedia.org/wiki/Gyroelongated_pentagonal_birotunda">Gyroelongated pentagonal birotunda</a>. %F A385488 Equals 10*sqrt(3) + 3*sqrt(25 + 10*sqrt(5)) = 10*A002194 + 3*sqrt(25 + 10*A002163). %F A385488 Equals the largest root of x^8 - 2100*x^6 + 1032750*x^4 - 121162500*x^2 + 1216265625. %e A385488 37.966236882756376008382607143722038862316542578226... %t A385488 First[RealDigits[10*Sqrt[3] + 3*Sqrt[25 + 10*Sqrt[5]], 10, 100]] (* or *) %t A385488 First[RealDigits[PolyhedronData["J48", "SurfaceArea"], 10, 100]] %Y A385488 Cf. A385264 (volume). %Y A385488 Cf. A002163, A002194, A384284, A385261, A385263. %K A385488 nonn,cons,easy %O A385488 2,1 %A A385488 _Paolo Xausa_, Jun 30 2025